@article{DAN_1971_199_1_a3,
     author = {V. B. Kudryavtsev},
     title = {On $S$-systems of functions of $k$-valued logic},
     journal = {Doklady Akademii Nauk},
     pages = {20--22},
     publisher = {mathdoc},
     volume = {199},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_199_1_a3/}
}